Phototherapy for psoriasis and other skin disordes

ABSTRACT

Single-core and multi-core microcapsules are provided, having multiple shells, at least one of which is formed of a complex a coacervate of two components of shell materials. The complex coacervate may be the same or different for each shell. Also provided are methods for making the microcapsules.

FIELD OF THE INVENTION

The present invention relates to an apparatus, a system and a method forthe phototherapy of psoriasis and other skin disorders.

BACKGROUND OF THE INVENTION

Psoriasis is a non-contagious skin disorder that most commonly appearsas inflamed swollen skin lesions covered with silvery white scale. Thismost common type of psoriasis is called “plaque psoriasis.” Psoriasiscomes in many different variations and degrees of severity. Differenttypes of psoriasis display characteristics such as pus-like blisters(pustular psoriasis), severe sloughing of the skin (erythrodermicpsoriasis), drop-like dots (guttate psoriasis) and smooth inflamedlesions in the flexural areas (inverse psoriasis). The degrees ofseverity of psoriasis ate divided into three important categories: mild,moderate and severe.

Skin cells are programmed to follow two possible programs: normal growthor wound healing. In a normal growth pattern, skin cells are created inthe basal cell layer, and then move up through the epidermis to thestratum corneum, the outermost layer of the skin. Dead cells are shedfrom the skin at about the same rate as new cells are produced,maintaining a balance. This normal process takes about 28 days from cellbirth to death. When skin is wounded, a wound healing program, alsoknown as regenerative maturation, is triggered. Cells are produced at amuch faster rate, theoretically to replace and repair the wound. Thereis also an increased blood supply and localized inflammation. In manyways, psoriatic skin is similar to exaggerated skin healing from a woundor reacting to a stimulus such as infection.

Lesional psoriasis is characterized by cell growth in the alternategrowth program. Although there is no wound at a psoriatic lesion, skincells, also referred to as keratinocytes, behave as if there is. Thesekeratinocytes switch from the normal growth program to regenerativematuration. Cells are created and pushed to the surface in as little as2-4 days, and the skin cannot shed the cells fast enough. The excessiveskin cells build up and form elevated, scaly lesions. The white scale(called “plaque”) that usually covers the lesion is composed of deadskin cells, and the redness of the lesion is caused by increased bloodsupply to the area of rapidly dividing skin cells.

It is known that ultraviolet (UV) light can suppress the inflammation inpsoriatic plaques and decrease the abnormal proliferation of epidermalkeratinocytes by affecting the DNA molecules of the radiated cells.

Phototherapy using ultraviolet light in general and specifically UVBlight, is a well-known and accepted treatment for widespread psoriasis.Typically, the whole or a large part of the body of the psoriaticpatient is irradiated by UV light (in most cases UVB—250-340 nm). Thelight is commonly generated by apparatus based on an array/matrix of UVemitting fluorescent light bulbs at relatively low UVB energy flux.Usually 30-40 such treatments are needed for the clearing of skinlesions. These current methods of psoriasis therapy have thedisadvantage that that the entire skin, including “healthy” skin parts,is exposed to harmful UV rays, and a long session of treatment isrequired to get only partial relief of symptoms.

Basic science and clinical research have shown that light with a narrowband in the wavelength range of 300-313 nm is most effective forpsoriasis therapy. The rationale for this UVB source stems fromelucidation of the UV action spectrum for clearing of psoriasis. In twostudies, it was determined that UV wavelengths (“mercury lines”) longerthan 313 nm were not effective in resolving psoriasis, whereaswavelengths shorter than 300 nm produced only UV burns (erytherna)without clearing psoriasis. Further dissection of wavelengths from 300to 313 nm established an “optimal” therapeutic index at 313 nm (definedas the lowest fraction of a Minimal Erythema Dose [MED] required toremit psoriatic skin lesions). Subsequently, a 311-nm UVB fluorescentbulb-based source was developed for treatment of psoriasis. SeveralEuropean studies have established the effectiveness of this treatmentwhen used 3 to 5 times a week at erythemogenic doses. In fact, narrowband UVB (NB-UVB) has proved to be even more effective than the modifiedGoeckerman regimen when used on a daily basis in patients with severerecalcitrant psoriasis (even in patients with highly pigmented skin).However, full-body aggressive administration of NB-UVB at erythemogenicor near-erythemogenic levels proved to be difficult because of somewhatunusual burning responses to this light source. Typical clearing regimentreatment with full-body narrow band fluorescent bulbs (TL-01) employs acumulative dose of 13 J/cm² (range 4 J/cm²-24 J/cm²). Clearing isachieved in 80% of treated patients in 4 weeks, 3 treatments/week, with50% of patients remaining clear after 6 months.

Hartman describes apparatus for targeted UV phototherapy of skindisorders, based on a UV arc lamp, in U.S. Pat. No. 6,413,268. The arclamp is housed in a base unit, which has one or more output ports towhich a flexible optical guide may be connected. The light from the arclamp is directed into the optical guide, which conveys the light to ahandpiece at its opposite end. The handpiece is used to deliver a shapedbeam of radiation to a target area of a patient. In one embodiment, thebase unit has two output ports, one for UVB radiation, and the other forUVA radiation. Optical guides may be connected to one or both of theports for delivering the desired type of radiation to the skin.

It is known that normal skin can be exposed to up to 3 MEDs withoutblistering while psoriatic skin may be exposed to up 3 times that dosewithout blistering. A therapy targeted only on psoriasis plaques,sparing the “healthy” skin, may thus employ higher fluences and mayshorten time to clearance. Another advantage of targeted phototherapymay be the sparing of non-psoriatic skin from harmful UV effects.Recently Asawanonda et al. treated psoriasis with an excimer laseremitting 308 nm. The MED in their patients was 203 mJ/cm². They reportthat medium fluences at 2-6 MED (400-1200 mJ/cm²) may result in clearingafter 2 weeks at 2 sessions a week. Fluences of up to 6 MEDs onpsoriasis plaques were well tolerated by all patients. Most patientsremained cleared after 2 months of follow-up.

Lasers are used by dermatologists for a variety of procedures.Increasingly, treating psoriasis with some types of lasers can be anoption for both physicians and patients to consider, but has itslimitations and operational constraints, as well as high purchase costs.

A device called X-trac™ is an excimer laser-based system, manufacturedby Photomedex of Radnor, Pa. It was approved by the U.S. Food and DrugAdministration (FDA) for psoriasis treatment, in early 2000. Other typesof excimer laser-based systems have also received FDA approval. Thelaser emits a high-intensity beam of UV light at a wavelength of 308 nm,close to the light delivered by conventional narrow-band UVB units. Themain disadvantages of this system are its narrow, high peak powerpulses, high purchasing and operational costs, complicated and expensivemaintenance and low reliability. Also, the system's large physical sizeis a limit in the small dermatologist's typical treatment room.

The largest study of X-trac enrolled 124 patients, and 80 patientscompleted the study, meaning the treatment cleared their psoriasis orthey had 10 treatments. Of those, 72 percent achieved at least 75percent improvement in their psoriasis, after an average of 6.2treatments. At least 90 percent improvement was seen in 35 percent ofthe patients, after an average of 7.5 treatments. How well an individualwill respond to the treatment varies. Photomedex reports that it takesan average of 4 to 10 sessions to see results, depending on theparticular case of psoriasis. Skin with psoriasis can handle much moreUT light than unaffected skin. Therefore, higher doses can be used withthe laser compared to traditional UVB units. For those who respond, thisshould mean quicker results: 10 or fewer laser sessions vs. 30 to 40treatments for regular UVB.

Selective photothermolysis is a method, described by Anderson andParrish in 1983 (“Selective Photothermolysis: Precise Microsurgery bySelective Absorption of Pulsed Radiation,” Science, Vol. 220, pp.524-527), for destroying certain diseased or unsightly tissue, on ornear the skin, with minimal damage to the surrounding healthy tissue.The tissue to be destroyed is generally characterized by significantlygreater optical absorption at some wavelength of electromagneticradiation than the surrounding tissue. The prior art methods includeirradiating the target and the surrounding tissue with pulsed lightradiation, usually visible radiation that is preferentially absorbed bythe target. The energy and duration of the pulses is such that thetarget is heated to between about 70 C and about 80 C, at whichtemperature the proteins of the target coagulate. Because the targetabsorbs the incident radiation much more strongly than the surroundingtissue, the surrounding tissue absorbs much less heat and, for at leastshort periods of exposure, does not reach a temperature to cause damage.However, the surrounding healthy tissue must be prevented from heatingup over an extended heating period.

Usually, the radiation source used in photothermolysis is a laser, forexample a flash lamp-pulsed dye laser. A laser source has the advantageof being inherently monochromatic. Other sources include broadbandsources used in conjunction with narrow band filters, as described, forexample, by Gustaffson in PCT patent publication WO 91/15264. A similardevice, called the “Photoderm-VL,” is manufactured by Lumenis Ltd. ofCalifornia. Suitable targets for selective photothermolysis includegeneral sub-surface veins, as well as birthmarks, port-wine stains,spider veins, and varicose veins, all of which tend to be much redderthan the surrounding tissue because of their higher concentration ofoxyhemoglobin-containing red blood cells.

Anderson and Parrish used light of a wavelength of 577 nm, correspondingto the 577 nm oxyhemoglobin absorption band. It was subsequentlydetermined (Tian, Morrison, and Kurban, “585 nm for the Treatment ofPort-Wine Stains,” Plastic and Reconstructive Surgery, vol. 86 no. 6 pp.1112-1117) that 585 nanometers is a more effective wavelength to use.

One constraint on the pulse duration used in photothermolysis is thatthe surrounding tissue must not be heated to the point that it, too,begins to coagulate. As the disorder (hereinafter sometimes referred toas the “target”) is heated, heat is conveyed by convection andconduction from the target to the cooler surrounding tissue. To keep thesurrounding tissue from being heated to the point of damage, the pulselength in the prior art is kept on the order of the target's thermalrelaxation time. For relatively small targets, such as birthmarks,port-wine stains, and spider veins, typical pulse lengths are on theorder of hundreds of microseconds. For varicose veins, pulse lengths onthe order of milliseconds should be used.

Selective photothermolysis also has been used to treat psoriatic skintissue. Flash-lamp-pumped pulsed dye laser beams have been used toselectively destroy cutaneous blood vessels. Light passing through theepidermis is preferentially absorbed by hemoglobin, the majorchromophore in the blood of the ectatic capillaries of the upper dermis.The radiant energy is converted to heat causing thermal damage andnecrosis in the target. Flash-lamp-pumped pulsed dye laser radiation ingeneral destroys the targeted dermal disorder. The problem is theprevention of damage to the surrounding healthy tissue. For example,port wine stains are known to be characterized by normal epidermisoverlying an abnormal plexus of dilated blood vessels located on a layerin the upper dermis.

The predominant endogenous and/or cutaneous chromophores that absorblight at the 585 nm wavelength produced by flash-lamp-pumped pulsed dyelaser are melanin and hemoglobin. Accordingly, the overlying epidermalpigment layer acts as an optical shield through which the light mustpass to reach the underlying lesion such as those caused by port winestain blood vessels. The absorption of laser energy by the melanincauses localized heating in the epidermis and reduces the light dosagereaching the target thereby decreasing the quantity of heat in thetargeted area, leading to sub-optimal blanching of the tissue disorderor necessitating increased time periods of treatment with consequentincreased risk of healthy tissue damage, unless steps are taken toprotect the healthy tissue.

Prior art cooling methods used to prevent damage to healthy tissueinclude the use of lens-like contact devices having high thermalconductivity and having a refractive index that enables the opticalradiation to be coupled to the epidermis, i.e., a refractive index ofapproximately 1.55. Thus, the contact device is preferably formed of ahigh-density material such as sapphire or other similar opticallytransparent glass or plastic. See, for example, U.S. Pat. No. 5,595,568,the disclosure of which is incorporated herein by reference.

SUMMARY OF THE INVENTION

There is thus a widely-recognized need for an effective way to treatareas affected by skin disorders, such as psoriatic plaques, vitiligo,and atopic dermatitis, and other localized skin disorders such askeloids and stretch marks scars with a well-concentrated UV lightsource. Such a UV source should overcome the limitations of both lowenergy-flux fluorescent-based devices and of the integrated energy of atrain of short pulses generated by high peak-power UVB laser-baseddevices. The source should provide a homogenous, comparatively smallexposure area, well-defined beam profile with output energy within aprescribed narrow spectral range.

Some embodiments of the present invention offer solutions to this needbased on simple and reliable types of UVB-emitting sources, having ahigh energy concentration and operating in CW mode or with long-pulseduration. These solutions provide the user with a constant UVB powerlevel during the entire exposure time. The treatment methods and relatedsystems, in accordance with these embodiments of the present invention,are simple and economical, enabling easy operation and minimalmaintenance procedures in the clinic, using low-cost yet reliableapparatus.

In other embodiments of the present invention, a system for treatingmultiple skin disorder indications generates output energy in one orseveral narrow spectral bands, selectable from UVB, UVA and violetbands. The energy may be generated by a single light source or multiplelight sources, having a high energy concentration and operating in CWmode or with long-pulse duration. These embodiments allow the user toelectrically select a narrow UVB, UVA or violet treatment band, or acombination of different bands, with constant power level during theentire exposure time. The selected band outputs are typically conveyedthrough a flexible light guide to the patient's skin. The system ispreferably configured so that a single light guide can be used to conveythe radiation in any or all of the bands, regardless of which bands areselected. This system thus provides a simple, economical, electricallyor electromechanically selectable set of dose and spectral energyexposure treatments, using a single treatment unit, which is easy tooperate and requires minimal maintenance.

In another embodiment, the UVB radiation-based treatment is combinedwith a photothermolysis treatment effect induced by a short-durationpulsed secondary light source.

In yet another embodiment, the output energy pattern of the apparatusand associated marking means provide the operator with the ability tocover homogeneously, in a matrix registration mode, the entire affectedskin area, while not affecting or damaging the non-lesional “healthyskin” around the psoriatic skin area.

The present invention thus provides an effective phototherapy methodthat is simple and economical to operate and is expected to effectivelyclear psoriasis, vitiligo, atopic dermatitis and other skin disorders ina small number of treatment sessions, with minimal after-effects. Therequired solution replaces commonly-used fluorescent-based treatmentsystems, which typically require 30-40 treatments, and laser systems,which are costly and difficult to maintain. In addition, the presentinvention may be used to treat conditions such as localized scleroderma,localized cutaneous T-cell lymphoma and hypopigmented scars.

There is therefore provided, in accordance with an embodiment of thepresent invention, apparatus for treatment of psoriasis and other skindisorders, including:

-   -   a radiation source, adapted to generate ultraviolet B (UVB)        radiation suitable for treatment of a psoriatic plaque; and    -   radiation delivery optics, coupled to the radiation source so as        to concentrate and deliver the generated UVB radiation to the        plaque with intensity of at least 75 mJ/cm² delivered to the        plaque over a period of less than 10 sec, and with a spectral        width of at least 30 nm, so as to engender clearing of the        plaque.

In an embodiment of the invention, the radiation source further includesa source of visible radiation suitable to photothermolyze blood vesselsin a vicinity of the plaque.

Typically, the radiation source includes a non-coherent UV source, whichis adapted to generate the UVB radiation continuously, wherein thenon-coherent UV source includes at least one of a group of sourcesconsisting of a metal halide gas discharge lamp and an excimer lamp.Additionally or alternatively, the radiation source includes a pulsedsource emitting at least one of visible radiation and near infrared (IR)radiation.

There is also provided, in accordance with an embodiment of the presentinvention, apparatus for treatment of a skin condition, including:

-   -   a radiation source, adapted to irradiate an area of the skin        with radiation in at least one of an ultraviolet, visible and        infrared spectral range; and    -   marking means, adapted to delineate the area on the skin        responsive to irradiation of the area by the radiation source.

Typically, the marking means includes one or more markers, adapted toprint a plurality of marks on the skin delineating the irradiated area,and the apparatus includes an arm supporting the radiation source, andan imaging device coupled to capture an image of the skin, and aprocessor adapted to analyze the marks on the skin appearing in theimage so as to guide the radiation source by controlling movement of thearm, responsive to the marks in the image.

Alternatively, the radiation source includes a radiation guide, which isbrought into proximity with the area of the skin so as to deliver theradiation thereto, and the marking means is adapted to mark a peripheryof the radiation guide.

The marking means may include a photosensitive substance, which isapplied to the skin prior to irradiating the area of the skin, whereinthe radiation causes a visible change in the photosensitive substance,thereby delineating the area.

There is additionally provided, in accordance with an embodiment of thepresent invention, apparatus for treatment of psoriasis, including:

-   -   a radiation source, adapted to irradiate a psoriatic area of        skin with ultraviolet (UV) radiation, so as to treat the        psoriasis;    -   an optical sensor, adapted to detect an optical quality of the        irradiated area; and    -   a dosage controller, coupled to receive an indication of the        optical quality from the optical sensor and to control the        radiation source responsive to the indication.

Typically, the optical sensor is adapted to sense a change in at leastone of a color and a texture of the irradiated area indicative oferytherna resulting from the radiation, and the dosage controller isadapted to control a flux of the radiation applied to the skin by theradiation source so as to engender a desired level of the erythema.

There is further provided, in accordance with an embodiment of thepresent invention, a method for treatment of psoriasis, including:

-   -   applying ultraviolet B (UVB) radiation to a psoriatic plaque;        and    -   applying visible radiation suitable to photothermolyze blood        vessels in a vicinity of the plaque, substantially        simultaneously with applying the UVB radiation.

Typically, the blood vessels photothermolyzed by the radiation in thevicinity of the plaque include blood vessels under the plaque.

There is moreover provided, in accordance with an embodiment of thepresent invention, a method for treating a skin condition, including:

-   -   irradiating an area of the skin with radiation in at least one        of an ultraviolet, visible and infrared spectral range; and    -   marking the area on the skin responsive to irradiation of the        area by the radiation source, so as to provide an indication of        the area of the skin that was treated.

There is furthermore provided, in accordance with an embodiment of thepresent invention, a method for treatment of psoriasis, including:

-   -   irradiating a psoriatic area of skin with ultraviolet (UV)        radiation, so as to treat the psoriasis;    -   detecting an optical quality of the irradiated area; and    -   controlling a level of the radiation responsive to the        indication.

The method may include, prior to irradiating the psoriatic area of theskin, applying a quickly-solidifying, self-peeling cream or gelmaterial, having UV energy protection capability including at least oneof absorption and reflection properties, to a healthy skin area on aperiphery of the psoriatic area.

There is also provided, in accordance with an embodiment of the presentinvention, apparatus for treatment of skin disorders, including:

-   -   a radiation source, adapted to generate ultraviolet (UV)        radiation suitable for treatment of skin affected by one or more        of the skin disorders; and    -   radiation delivery optics, coupled to the radiation source so as        to concentrate and deliver the generated UV radiation directly        to the affected skin with an energy flux level per single        treatment and specific affected skin area selected from an        energy radiation flux group consisting of at least a radiation        flux equal or higher than 50 mJ/cm² in less than 30 sec per        treatment and a radiation flux higher than 1.5 MED (Minimum        Erythema Dose),    -   wherein the UV radiation is in a spectral range of 296-390 nm        and includes at least one spectral line of substantial intensity        having a bandwidth of at least 1 nm, wherein the spectral line        is selected so as to engender clearing of the affected skin.

Typically, the radiation source includes a non-coherent UV source, whichis adapted to generate the UVB radiation continuously during apredefined exposure time. Preferably, the UV radiation includes aradiation band in the spectral range of 296-313 nm, and the radiationband includes multiple spectral lines, which are chosen so as to enhancean efficacy of the treatment. More preferably, the spectral line iswithin the spectral range of 296-305 nm, and the spectral line is chosenso as to facilitate the efficacy of the treatment by at least one ofmaximizing treatment effect and minimizing treatment time of theaffected skin area. Most preferably, the spectral line emission iswithin the spectral range of 300-304 nm.

In embodiments of the present invention, the non-coherent radiationsource includes at least one of a group of sources consisting of a metalhalide gas discharge lamp, a laser diode matrix, a light emitting diode(LED) matrix, and an excimer lamp.

Typically, the radiation delivery optics are adapted to limit anexposure area of the radiation to the affected skin, wherein theradiation delivery optics include one of a selection of interchangeablelight guides, which are adapted to direct the radiation toward theaffected skin during the treatment, and wherein the light guides areselectable so as to match an output aperture of the selected light guideto a size and shape of the affected skin. In an embodiment of thepresent invention, the output apertures of the interchangeable lightguides are selected from a group including aperture areas of at least200 mm², 400 mm² and 2500 mm². Additionally or alternatively, theradiation delivery optics further include aperture shaping optics at theoutput aperture so as to provide an aperture shape that is adapted foroptimal plaque area energy coverage.

In an embodiment of the invention, a module containing the radiationsource and the radiation delivery optics, and an articulated arm, whichis coupled to suspend and position the module relative to the affectedskin.

Typically, the radiation delivery optics include an optical filter,which is adapted to limit the spectral range of energy emitted by thelight source is limited to the spectral range above 296 nm. Additionallyor alternatively, the radiation delivery optics include an opticalbandpass filter, which is adapted to limit the spectral range of energyemitted by the light source to the spectral range above 296 nm and under390 nm.

In embodiments of the invention, the radiation source is adapted toprovide a continuous energy output during treatment of the affectedskin, with a momentary output peak power smaller than 10 kW/cm². Theradiation source may includes a metal halide lamp, whose output spectrumincludes spectral lines at 303, 306, 308, 309, and 312 nm.

In an embodiment of the invention, the apparatus is adapted to determinethe radiation flux corresponding to the MED by determining a minimumenergy dosage creating erytherna on normal skin in a vicinity of theaffected skin area, whereby operating parameters of the apparatus areset to the radiation flux thus determined.

There is additionally provided, in accordance with an embodiment of thepresent invention, a lamp for treatment of skin disorders, the lampincluding:

-   -   a transparent envelope;    -   a mixture of species contained within the envelope, the species        including a halogen and a plurality of metals selected from a        group of metals consisting of mercury, bismuth, aluminum,        cesium, iron and gallium; and    -   discharge electrodes disposed within the envelope, so as to        generate an arc within the mixture of species, thereby causing        emission of ultraviolet radiation.

Typically, the species are pressurized within the envelope, so thatwhile the discharge electrodes are generating the arc, a gas pressurewithin the envelope is greater than 5 atm.

There is further provided, in accordance with an embodiment of thepresent invention, apparatus for treatment of skin disorders, including:

-   -   a radiation source, which is adapted to generate radiation in        multiple spectral bands;    -   a radiation guide, which is optically coupled to receive the        radiation in all of the multiple spectral bands, and to convey        the received radiation to an area of skin affected by one of the        disorders, so as to treat the affected area; and    -   a band selector, which is adapted to select one or more of the        multiple spectral bands to be conveyed by the radiation guide,        in response to a therapeutic indication.

Typically, the radiation source includes a metal halide arc lamp,wherein the metal halide arc lamp is a high-pressure lamp, containing atleast one of bismuth, cesium, iron and gallium.

The multiple spectral bands may include at least one band in each of anultraviolet A (UVA) range, an ultraviolet B (UVB) range, and a visiblerange. In embodiments of the invention, the visible range includes aviolet light range and/or a red light range.

In an embodiment of the invention, the band selector is adapted toselect at least two of the spectral bands to be conveyed by theradiation guide simultaneously, wherein the at least two of the bandsinclude the at least one band in one of the UVA and UVB ranges and theat least one band in the visible range. For example, the at least oneband in the one of the UVA and UVB ranges may include one or morewavelengths in the UVB range that provide effective treatment of apsoriatic plaque, while the at least one band in the visible rangeincludes violet light suitable for treating inflammation associated withthe plaque.

In another embodiment, the radiation source includes a plurality oflamps, each operating in one or more of the spectral bands, and a beamcombiner for combining the radiation from the plurality of the lamps tobe received by the radiation guide. The plurality of lamps may includeelectrical discharge lamps and/or solid-state light sources. Typically,the beam combiner includes one or more dichroic mirrors, which areadapted to selectively reflect the radiation emitted by the lamps.Additionally or alternatively, the band selector is arranged to actuateone or more of the lamps to operate so as to provide the selected one ormore of the spectral bands.

Further additionally or alternatively, the band selector includes one ormore optical filters, having a selectable spectral passband.

In embodiments of the invention, the radiation guide includes at leastone of a fiberoptic light guide and a liquid-filled light guide.

The radiation guide includes a proximal end, which is coupled to receivethe radiation, and a distal end, which is adapted to deliver theradiation to the area of the skin, and the apparatus may furtherinclude:

-   -   a receptacle, for receiving the distal end of the radiation        guide;    -   a detector, which is coupled to receive the radiation emitted        from the distal end of the radiation guide when the radiation        guide is inserted in the receptacle, and to generate a signal in        response to an intensity of the radiation; and    -   a controller, which is coupled to receive the signal from the        detector and to determine, based on the signal, an output level        of the apparatus.

Typically, the controller is adapted to adjust an operating level of theradiation source in response to the signal, so as to adjust the outputlevel to a predetermined value.

In a further embodiment, the apparatus includes a controller having auser interface, which is operable by an operator of the apparatus toinput the therapeutic indication to the band selector. The userinterface may be further operable by the operator to initiate aprocedure, using the apparatus, for determining a Minimal Erythema Dose(MED) of a patient in treatment, and the controller is adapted to set alevel of the radiation to be applied to the affected area of the skin ofthe patient based on the determined MED. Typically, the controllerincludes a memory, and the user interface is further operable by theoperator to record and recall a treatment history of a patient intreatment using the apparatus.

There is moreover provided, in accordance with an embodiment of thepresent invention, a method for treatment of skin disorders, including:

-   -   directing radiation in multiple spectral bands toward an input        end of a radiation guide;    -   selecting one or more of the multiple spectral bands to be input        to the radiation guide through the input end, in response to a        therapeutic indication with respect to an area of skin affected        by one of the disorders; and    -   applying an output end of the radiation guide to the affected        area of the skin as to treat the affected area.

The present invention will be more fully understood from the followingdetailed description of the embodiments thereof taken together with thedrawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, pictorial illustration of a system forphototherapy, in accordance with one embodiment of the presentinvention;

FIG. 2 is a schematic, internal view of an optical head used inphototherapeutic irradiation of the skin, in accordance with oneembodiment of the present invention;

FIG. 3 is a block diagram that schematically illustrates circuitry usedin controlling phototherapeutic energy dosage, in accordance withanother embodiment of the present invention;

FIG. 4A is a schematic side view of phototherapeutic apparatus withautomated registration of the treated area, in accordance with a oneembodiment of the present invention;

FIG. 4B is a schematic top view of skin of a patient that has beentreated using the apparatus of FIG. 4A;

FIG. 5A is a schematic cross-sectional side view of optics, including anelliptical reflector and light guide, used to concentratephototherapeutic radiation on the skin of a patient, in accordance withanother embodiment of the present invention;

FIG. 5B is a schematic optical diagram showing details of the ellipticalreflector of FIG. 5A;

FIG. 5C is a schematic, pictorial illustration of the light guide ofFIG. 5A;

FIG. 6A is a schematic, pictorial illustration of an optical head usedin dual-band phototherapy, in accordance with one embodiment of thepresent invention;

FIG. 6B is a schematic side view of an optical head used in dual-bandphototherapy, in accordance with another embodiment of the presentinvention;

FIG. 6C is a schematic side view of an optical head used in dual-bandphototherapy, in accordance with yet another embodiment of the presentinvention;

FIG. 7 is a plot that schematically illustrates spectral lines and bandsused in dual-band phototherapy, in accordance with another embodiment ofthe present invention;

FIG. 8 is a plot that schematically illustrates a spectral line andassociated spectral band used in UVB phototherapy, in accordance withone embodiment of the present invention;

FIG. 9A is a schematic cross-sectional side view of an excimer lampillumination source that is integrated within an optical head used inUVB phototherapy, wherein the output energy is directed perpendicular tothe mechanical axis of the lamp, in accordance with another embodimentof the present invention;

FIG. 9B is a schematic cross-sectional side view of an excimer lampillumination source that is integrated within the optical head used inUVB phototherapy, wherein the output energy is directed alongside themechanical axis of the lamp, in accordance with another embodiment ofthe present invention;

FIG. 10 is a schematic cross-sectional side view of an optical head usedin UVB phototherapy based on an excimer lamp, in accordance with yetanother embodiment of the present invention.

FIGS. 11A and 11B are schematic, pictorial illustrations of systems forphototherapy, in accordance with further embodiments of the presentinvention;

FIG. 11A is a schematic, pictorial illustration of a system forphototherapy in a use mode, in accordance with another embodiment of thepresent invention;

FIG. 11B is a schematic, pictorial illustration of a system forphototherapy in a standby mode, in accordance with another embodiment ofthe present invention;

FIG. 12A is a schematic cross-sectional side view of optics used in asystem for phototherapy, in accordance with an embodiment of the presentinvention;

FIG. 12B is a schematic, pictorial illustration showing further detailsof the optics of FIG. 12A;

FIG. 12C is a schematic optical diagram showing optics used in a systemfor phototherapy, in accordance with another embodiment of the presentinvention;

FIGS. 12D and 12E are schematic optical diagram showing optics used insystems for multi-band phototherapy, in accordance with otherembodiments of the present invention;

FIG. 13 is a schematic, pictorial, partly cutaway illustration showingdetails of an optical treatment head and receptacle used in a system forphototherapy, in accordance with an embodiment of the present invention;

FIGS. 14 and 15 are plots that schematically illustrate output spectralbands of a system for phototherapy, in accordance with embodiments ofthe present invention; and

FIGS. 16A-16E are schematic representations of computer screens used ina graphical user interface of a system for phototherapy, in accordancewith an embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 is a schematic, pictorial illustration of a system 10 forphototherapeutic treatment of psoriasis and other skin disorders, inaccordance with one embodiment of the present invention. System 10comprises an optical head 12, which is used to irradiate the skin of apatient (not shown), who typically lies on a treatment table 14. Detailsof optical head 12, in a number of different, alternative embodiments,are shown in the figures that follow. Optical head 12 is connected to apower supply and control console 16 by an adjustable suspension arm 18,which allows an operator of system 10 to adjust the vertical, horizontaland radial placement of the optical head relative to the patient's body.

Adjustable suspension arm 18 can be made for pure mechanical movement,to be manipulated by an operator of head 12, the arm having integratedbalancing weights on each arm section. Alternatively, a balancingcounter-tension spring is integrated into at least one of the sectionsof arm 18. In another embodiment an electromechanical movement controlunit, such as a motor, is integrated into the movement axis of each ofthe sections of arm 12, so as to enable electrical control of the headposition in space. Thus, the vertical, horizontal and radial placementof the optical head are adjusted relative to the patient's body. In oneembodiment of system 10, the movement and positioning control of unit 12is done by an embedded computer in control console 16, wherein thepositioning of head 12 is defined by the computerized analysis of theimage of the treated affected area, as visualized by a camera unit 24.Console 16 includes a control panel 20, enabling the operator to adjustthe position of head 12, as well as to control treatment parameters; tooperate, generate and digitally store images using camera unit 24; andto receive feedback from system 10.

Optical head 12 preferably generates intense, ultraviolet (UV)radiation, which is conveyed to a treatment area on the patient's skinby a light guide 22. Preferably, the radiation comprises broadband,continuous-wave (CW), non-coherent UVB radiation, which is applied atdosages above the MED threshold, sufficient to clear psoriatic plaques.(Here “broadband” refers to radiation bandwidth greater than about 30nm.) Alternatively, system 10 and optical head 12 may be used to applynarrowband and/or pulsed UV radiation. In some embodiments, describedbelow with reference to FIGS. 6A-6C and 7, the UV radiation is appliedin concert with visible and/or infrared (IR) radiation, so as to combinethe effects of UV treatment with photothermolysis. Light guide 22concentrates the radiation on a small, well-defined area of the skin, soas to provide the high energy flux required for effective treatment ofconditions such as psoriasis, while avoiding unwanted irradiation ofhealthy skin areas. System 10 may also be used to treat other skinconditions, such as vitiligo.

Camera unit 24 serves as an erytherna sensor, typically comprising ahigh-resolution color video imaging device, used to monitor the treatedarea of the skin. Unit 24 preferably comprises a zoom lens 26, enablingthe sensor to be aimed and focused properly on the treatment area.Preferably, unit 24 also includes integral illumination sources 28, mostpreferably based on a light emitting diode (LED) matrix orphotoluminescent lamps, emitting white light. Console 16 monitors theredness and, optionally, other parameters provided by unit 24 in orderto control the duration and intensity of the treatment. Details of thesemonitoring and control functions are described below with reference toFIG. 3.

FIG. 2 is a schematic, internal view of optical head 12, in accordancewith a one embodiment of the present invention. An enclosure 30 containsa lamp 32 with an elliptical reflector 34. These elements are shown ingreater detail in FIGS. 5A and 5B below. Lamp 32 preferably comprises ametal-halide lamp short arc high pressure or medium pressure lamp,containing mercury and possible other additives, such as bismuth,aluminum and iron. When integrated as a metal-halide additive to a metalhalide lamp, aluminum has spectral emission lines at 308 nm and 309 nm,while bismuth has an emission line at 306 nm. Mercury has emission linesin the relevant UVB treatment spectrum of 296 nm, 303 μm, and 313 nm.The mercury content in a typical 400 watt metal halide lamp used in oneembodiment of the invention is in the range of 30-50 mg. In anotherembodiment, bismuth-halides are added to the lamp volume in a typicalweight of 0.1-0.5 mg and aluminum-halides of weight 0.1-0.5 mg. Iron maybe added to further enhance the UVA spectral band output of the gasdischarge lamp. Alternatively, other types of lamps may be used, such asexcimer lamps, as detailed in the figures and description that follow.As shown in FIG. 6C below, the lamp and enclosure may be cooled by acoolant flowing through a heat-exchanger coil 36, along with optionalexhaust fans 38 (which also remove ozone that may accumulate in theenclosure). Light baffles 40 prevent the escape of stray UV lightthrough fans 38.

Reflector 34 focuses radiation emitted by lamp 32 into light guide 22.An optional hot mirror 42 (i.e., a short-pass filter) cuts offlong-wavelength radiation emitted by the lamp and reflects thisradiation towards fans 38. An iris 44 is adjustable in size to controlthe intensity of radiation that reaches the light guide. A motor 46 (oralternatively, a solenoid) opens and closes a shutter 48 to control theduration of treatment. A UV bandpass filter 50 selects the range ofwavelengths that will be conveyed from lamp 32 to the patient's skin.Preferably, filter 50 eliminates wavelengths below 300 nm, which areknown to cause erytherna while providing little therapeutic benefit forpsoriasis. Due to the high angular and thermal sensitivity of narrowbandinterference filters as to their central wavelength for spectralselection, as well as their typical low peak-wavelength transmission(15-30% typical), as well as for economical reasons due to their highcost, absorption filters may be preferred for this purpose. Theabsorption filters have economical prices and are limited in theirspectral bandwidth selection capabilities in the UV spectrum. Typically,such filters have a pass band in the range of 100 nm to 30 nm minimumspectral bandwidth.

In one preferred embodiment a WG305 bandpass filter, made by Schott(Germany) is used to filter the required UV spectrum. In anotherembodiment a combination of two filters is used, installed in series,such as the Schott WG305 and UG11 filters. This combination is requiredto cut off more energy in the more hazardous UV spectrum under 300 nm.Optionally, filter 50 is adjustable to select the optimal UVB wavelengthband based on characteristics of the patient's skin. The exposureduration of the affected skin area, controlled by shutter 48, is alsobased on the characteristics of the patient's skin. Thesecharacteristics may be determined by sensor 24 (FIG. 1) and/or may beinput by the operator of system 10. The optical elements in head 12 arepreferably mounted on an optical bend 52, which is built into enclosure30.

Light guide 22 comprises a tapered hollow prism or conical structure,whose inner surface is coated to provide efficient reflection of the UVBradiation emitted by lamp 32. Optionally, the hollow structure containsa UV-transmitting liquid. Alternatively, the light guide may comprise asolid structure, made of suitable UV-transparent material, such asquartz or sapphire. Structures that combine hollow and solid sectionsmay also be used. The light guide is tapered to provide enhancedconcentration of the therapeutic radiation on the skin. Preferably, thelight guide terminates in a removable hood 54, which is brought intocontact with a surface 56 of the patient's skin. Further preferably, agel is applied to surface 56 before bringing hood 54 into contacttherewith, in order to cool the skin, as well as to improve opticalindex matching between the light guide and the skin surface. Becausehood 54 is far removed from lamp 32, it typically remains at or nearroom temperature and does not itself contribute to heating of the skin.Alternatively hood 54 is further cooled to close to zero degrees Celsiusto provide enhanced cooling of the irradiated skin area, in order toremove excess heat from the irradiated skin, thus avoiding or reducingthermal damage.

FIG. 3 is a block diagram that schematically illustrates dosage controlcircuitry 60 used in system 10, in accordance with another embodiment ofthe present invention. A central processing unit (CPU) 62, typicallycontained in console 16, receives data input from the erytherna sensor.As noted above, the sensor preferably comprises high-resolution digitalimaging device 24, but it may, additionally or alternatively, comprise adedicated composite color analyzer and/or skin texture sensor. Such asensor may be integrated into the imaging module. The images output bythe sensor are processed using image processing techniques known in theart to determine the redness of the skin and other features indicativeof the effect of the treatment and the level of erythema created on thetreated skin. Still further alternatively, the sensor may be a separateunit (not shown in FIG. 1) that is operated off-line and is attached bya cable to system 10.

The erythema sensor may be used either for on-line sensing, givingfeedback during treatment with system 10, or for intermittent, off-lineevaluation, or for both. In the off-line evaluation mode, erythematesting is used to define the exposure dose at the beginning of thecourse of treatment, by exposing the patient's skin to various dosagelevels and testing the skin reaction after 24-48 hours to determine whatdose corresponded to the erythema level threshold. The results of boththis off-line evaluation and of on-line monitoring are stored in apatient database 64 for subsequent reference by CPU 62 and by theoperator of system 10. Before and after each treatment, sensor 24records the condition of the skin in the database. The doctoradministering the treatment is thus able to see how the local skincondition changes from one treatment to another via a user interface 66.

Based on input from the erythema sensor and from database 64, CPU 62operates a dosage control output 68 to regulate the functions of opticalhead 12. These functions typically include the radiation intensity(preferably controlled by the aperture size of iris 44), the exposureduration and, optionally the range of exposure wavelengths. In additionto automatic dosage control by CPU, the doctor administering thetreatment can manually control the dosage parameters via user interface66.

FIG. 4A is a side view of optical head 12 showing details of a markingdevice 70 used in automated registration of the treated area of skin 56,in accordance with another embodiment of the present invention. Device70 is mounted on light guide 22 (or specifically on hood 54, shown inFIG. 2) and is connected by a cable 72 to CPU 62 via optical head 12. Ineach position at which the light guide administers radiation to skin 56,CPU 62 controls a set of markers 74 to mark the periphery of the treatedarea. Device 70 thus allows accurate registration and tracking of thearea that has been treated, even if the patient moves during treatment.In one embodiment, device 70 comprises an ink jet module, and markers 74comprise ink ports, preferably three or four such ports.

In another embodiment, the gel applied to skin 56 before administrationof the phototherapy comprises a dyed photopolymer. Markers 74 compriselaser diodes or LEDs, which activate the photopolymer, causing it tochange color. Alternatively, the photopolymer may be UV-activated, sothat the radiation applied by light guide 22 causes the color change,typically after 1-2 sec of irradiation.

FIG. 4B is a schematic top view of a region of skin 56 that has beentreated using system 10 and marked by means of marking device 70. Inthis example, a psoriatic plaque 78 has been treated by application ofUV radiation to a grid of rectangular treatment areas 80, defined by therectangular shape of light guide 22. Each area 80 is marked by markers74 with three to four spots 82, 84 at its corners. Each spot 82 that isinside the treatment region receives radiation from all four of thesurrounding treatment areas 80. Although these spots are outside theactual area contacted by the light guide, the gradual drop-off ofradiation around the edges of the light guide ensures that theseinternal spots 82 will receive sufficient therapeutic radiation.Similarly, border areas 86 within the treatment region receivesufficient radiation from adjoining treatment areas 80.

Spots 84 mark the outer extreme of the treatment region, whichpreferably corresponds to the edge of plaque 78. The UV radiationtypically drops off sharply at the spots and beyond, so that normal,healthy skin is not substantially affected by the UV radiation. Thus, byobserving and controlling the pattern of spots 82, 84, the operator ofsystem 10 can ensure that pathological regions of the skin receive anaccurate, intense, substantially uniform dose of radiation, whilepreventing undesired exposure of the remaining skin.

In another embodiment, the image captured by camera unit 24 of plaque 78and its edge contours, including spots 82, 84 and the matrix oftreatment areas 80, is analyzed in real time by CPU 62 in system 10. Aset of electromechanical actuators and/or motors that is integrated intoadjustable suspension arm 18 is activated by the CPU through D/A drivers(not shown) using the analyzed image content data. In this way, the CPUautomatically moves treatment head 12 from one treatment position to thenext, in order to optimally cover the entire affected area. Spots 82, 84serve as guide marks for the CPU.

In another embodiment of the invention, the area of the skin 56surrounding and in proximity to the perimeter of the affected skin area,is coated by a UV radiation absorption protection layer, prior to eachof the treatment procedure sessions. The material is preferably based ona fast-curing gel or cream containing additive material or dyes thathave high absorption and/or reflection to UV radiation. Such materialsinclude titanium oxide and barium titanate. The material is applied by abrush or any other appropriate mechanical means and is used for maskingthe non-affected skin area in close proximity, typically within 3-5 cm,around the perimeter of the affected area. The masking material aftercuring is of solid yet flexible texture, similar to peeling maskmaterial used for skin treatment in cosmetic procedures, and can beeasily peeled off by pulling the material layer off the coated area, ina simple procedure done by the operator of system 10.

FIG. 5A is an optical ray trace diagram showing details of the operationof reflector 34 and light guide 22, in accordance with a anotherembodiment of the present invention. As shown by rays 90 and 94, thearrangement of elliptical reflector 34 and tapered light guide 22provides highly-efficient collection of the radiation emitted by lamp32. Ray 94 is the ray characterizing the maximum acceptance angle oflight-guide 22, relative to the bundle of collected rays emerging fromreflector 34. Optionally, reflector 34 contains a number ofsub-reflector units or flaps 35, preferably square in shape andperpendicular to the plane of an exit aperture 106 of the reflector,held by a frame 37 fitted to the aperture. The flaps are designed toreduce the output numerical aperture of the emerging light ray bundlefrom reflector 34 by converting part of the diverging rays, which wouldotherwise be lost, back to the acceptance angle range of light-guide 22.Thus, rays such as ray 92 are able to enter the aperture of light-guide22 at an angle that will enable the entering ray to emerge at the exitaperture of the light-guide. As mentioned above, a layer of gel 96 ispreferably applied to skin 56, in order to improve the optical indexmatching between the end of light guide 22 and the skin.

FIG. 5B is a schematic optical diagram showing details of reflector 34,which corresponds to a portion of an ellipse 100. Lamp 32 is mounted ata first focus 101 of ellipse 100, so that radiation emitted by the lampis concentrated at a second focus 102. For efficient collection of theenergy from lamp 32, this second focus 102 is preferably at or near theupper surface of light guide 22. Extreme rays 104 emitted from lamp 32define the numerical aperture, and hence the efficiency, of the opticalsystem. The angle of rays 104 is, in turn, determined by the geometricalproperties of ellipse 100 and of mirror 34, including the major andminor axes of the ellipse and a clear aperture 106 defined by the cut ofthe mirror.

As lamp 32 has an elongated shape and is not a perfect point source insome embodiments, due to the nature and the shape of the glowing plasmaof an arc light source, reflector 34 may alternatively have asemi-elliptical or other non-symmetric cross-section, so as to moreefficiently collect the radiation emitted by the lamp.

FIG. 5C is a schematic, pictorial illustration showing one possibleconfiguration of light guide 22, in accordance with another embodimentof the present invention. As noted above, the light guide is preferablytapered from a larger entry height 110, at which the rays from lamp 32enter the light guide, to a smaller exit height 112. In the picturedembodiment, the exit aperture of the light guide has a larger width 114than its height 112, in order to provide energy concentration,generating a larger energy flux, and to create the convenient treatmentarea coverage of the rectangular irradiation profile shown, for example,in FIG. 4B. Typically, height 112 is about 20 mm, while width 114 isabout 40 mm.

In other embodiments, different sizes and height/width ratios may beused. Light guide 22 may alternatively be shaped to transform the inputbeam from a square or rectangular profile to an elliptical or circularprofile, or vice versa. The output beam profile of the light guide canthus be selected in order to meet the specific treatment requirements ineach case. Optionally, different light guides can be interchanged by theoperator of system 10, either by replacing the entire light guide orreplacing only hood 54 (FIG. 2).

FIG. 6A is schematic, pictorial illustration of an optical head 120 usedto apply dual-band phototherapy to skin 56, in accordance with oneembodiment of the present invention. Head 120 is shown in a partialcutaway view, so that both the inside and outside of the head arevisible. The optical head comprises UV lamp 32, as described above,along with a lamp 122 that emits in the red range, preferably between580 and 635 nm, which is effective in causing photothermolysis of bloodvessels in the psoriatic tissue under treatment. Psoriasis-affectedepidermal tissue has an underlying network of blood vessels, notablycapillaries, that absorb incident radiation. Because of their smalldiameter, these vessels have short thermal relaxation times, and shortexposure times are therefore preferable for use in photothermolyzingthem. Preferably, lamp 122 comprises a gas discharge lamp, such as axenon lamp, which most preferably operates in a pulsed mode, emittingpulses that are typically of 50-500 ms in duration. Alternatively, lamp122 may be replaced by a high-power LED array or by a suitable lasersource.

As noted above, by combining lamps 32 and 122 in a single optical head,system 10 is able to administer simultaneous UV phototherapy topsoriatic plaques and photothermolysis to coagulate the vasculatureassociated with the plaques. Both UV phototherapy and photothermolysisare threshold-type effects, meaning that the radiation flux incident onthe plaque must be above a certain minimum level in order to achieveuseful therapeutic results. On the other hand, increasing the incidentflux in either of these therapies has undesirable side effects,including erythema (in the case of UV) and thermal damage to surroundingskin and underlying tissue layers (for intense visible/IR exposure). Theeffects of UV and visible/IR irradiation on psoriatic plaques arebiologically independent of one another, with UV irradiation affectingmainly the cell structure of the outermost skin layers, whilephotothermolysis operates on the blood vessels deeper within the tissue.In terms of therapeutic benefit, the two types of radiation arecomplementary. Therefore, by combining lamps 32 and 122 in a singleunit, it is possible to achieve enhanced therapeutic effect and to lowerthe therapeutic thresholds of both types of irradiation, withoutincreasing the incidence of erythema and thermal damage.

In the embodiment shown in FIG. 6A, each of lamps 32 and 122 is mountedat the focus of a respective concave reflector 124, preferably aparabolic reflector. The remainder of head 120 is spherical in shape andhas an internal coating 126 that diffusely reflects incident radiationover a wide range of wavelengths, from UVB through near IR. Head 120thus acts as an integrating sphere, with an output window 128 that isplaced against skin 56. Rays 130 emitted by both of lamps 32 and 122 arereflected diffusely from the interior wall of the sphere until theyimpinge on skin 56 through window 128.

FIG. 6B is a schematic side view of another optical head 140 for use indual-band phototherapy, in accordance with another embodiment of thepresent invention. In this embodiment, UV lamp 32 is mounted at thefocus of elliptical reflector 34, which focuses the UV radiation intolight guide 22, as described above. Visible radiation forphotothermolysis is provided by an array of high-power IR emittingmodules 142, based on LEDs or diode lasers. Each of the modules includescollimating optics 145 and a semiconductor chip 143. The modules aremounted against respective prisms 144. These prisms are fixed, typicallyby optical cement, to the sides of light guide 22, so as to inject thevisible light emitted by modules 142 into the light guide. The combinedUV and visible beams are then incident on skin 56.

FIG. 6C is a schematic side view of still another optical head 150 foruse in dual-band phototherapy, in accordance with another embodiment ofthe present invention. The arrangement of head 150 is similar to that ofhead 12, shown in FIG. 2, and only the differences in the presentembodiment are described here. Head 150 includes a visible light source152, based on a pulsed lamp 154, such as a gas discharge lamp or on aLED or diode laser array, in addition to UV lamp 32. Alternatively, lamp154 may be replaced by a suitable laser. Light from lamp 154 iscollimated by a lens 156 and is reflected into light guide 22 by adichroic reflector 158, which reflects visible light while passing UVradiation emitted by UV lamp 32. Cooling coils 39 are preferably appliedto light guide 22, while cooling coil 36 cools housing 30. Cooling coil39 can alternatively comprise Peltier effect-based cooling elements,both alternatives having the function of keeping the light guide at atemperature much under room temperature, preferably close to zerotemperature, in order to extract from and dispose of the excess heatgenerated by the combined UV and visible/IR radiation at the irradiatedtissue.

FIG. 7 is a spectral plot of radiation generated by a dual-band opticalsource for performing combined UV and visible treatment of psoriaticplaques, in accordance with yet another embodiment of the presentinvention. As noted above, lamp 32 preferably comprises a metal-halidelamp, containing mercury, as is known in the art. The lamp may containother metal additives, as well, such as tantalum, vanadium and/orcesium, as well as halogens, in order to provide visible radiation thathas useful photothermolytic effect. In this case, as long as the visibleradiation is sufficiently strong, it may be possible to carry out thecombined therapy without a separate visible light source, in distinctionto the embodiments of FIGS. 6A-6C.

Thus, in the spectrum shown in FIG. 7, lines 160, 162 and 164 arecharacteristic mercury-halide spectral features. Lines 160 are the twoUVB spectral lines that are commonly used using fluorescent lightsources for treating psoriatic plaques by DNA destruction in the 300-320nm range. Line 162 is a UVA line, while lines 164 are violet lines thatare thought to provide useful secondary healing effects, operating onthe body's auto-immune system. Lines 166 in the yellow/orange range,emitted due to the optional metal additives mentioned above, havephotocoagulative (photothermolytic) effects on the small blood vesselsthat nourish the affected tissues.

In addition to these lines (or instead of lines 166), a broad band 168is generated by an additional light source provided for the purpose ofphotothermolysis, such as lamps 122, 142 or 152, shown in FIGS. 6A-6C.Alternatively, other spectral distributions may be used. Furthermore,although the use of this combination of UV and visible radiation bandsis described herein mainly with reference to psoriasis, those skilled inthe art will appreciated that the combined effects of UV phototherapywith visible-light photothermolysis may also have therapeutic benefit intreatment of other skin disorders.

FIG. 8 is a spectral plot of typical radiation generated by an excimerlamp-based light source for performing narrow band UVB, or combined UVand visible treatment of psoriatic plaques, in accordance with yetanother embodiment of the present invention. In the spectrum shown inFIG. 8, line 180 is characteristic of XeCl excimer radiation. It issimilar to the narrow UVB spectral line that is produced by excimerlaser light sources for treating psoriatic plaques by DNA destruction inthe 300-320 nm range, but has a broader spectral width. The typicalexcimer laser bandwidth is 0.3±0.2 nm while the typical spectralbandwidth of an excimer lamp output is 2 nm. The main benefits of theexcimer lamp light source in comparison to the excimer laser arecontinuous-wave operation (CW), non-coherence, compact size, spectraloutput, tunability by driving frequency, higher reliability and muchlower costs.

FIG. 9A is a typical cross-sectional image of an excimer lamp 200 usedas a light source in skin treatment apparatus according to oneembodiment of the invention. The lamp is constructed of two concentricglass tubes 214 and 208, wherein an excimer gas is inserted and trappedin a space 212 between the two tubes. When a high frequency (RF)alternating electric field is induced by a power source 218 between twoelectrodes 210 and 216, the gas in the volume between the two tubesstarts to glow. UV light 221 emerges between the external elements ofelectrode 210. Cooling liquid is circulated in a volume 220 of innertube 214 in order to enable stable light output and operation of thelight source.

FIG. 9B is a cross-sectional image of another excimer lamp 240 used as alight source in skin treatment apparatus according to another embodimentof the invention. The lamp is constructed of two concentric glass tubes255 and 256, preferably quartz, wherein an excimer gas is inserted andtrapped in a space 250 between the two tubes. A light-reflectiveelectrode 253 is coated on the external surface perimeter of inner tube255, and a second electrode 254 is coated on the internal surfaceperimeter of outer tube 256. When a high frequency (RF) alternatingelectric field is induced between the two electrodes 253 and 254, thegas in the volume between the two tubes starts to glow and light 258 istrapped and directed out of space 250 by multiple reflections betweenthe two reflective electrodes 253 and 254. Part of the generated lightthat is not reflected by electrodes 253 and 254 is trapped in the glasswalls of tubes 255 and 256 and is directed out by multiple internalreflections within the walls, acting as light guides.

The light emerging from lamp 240 has an annular or ring shape 261, witha low- to zero-energy area in its center 260. The ring-shaped outputenergy beam emerges through the entire aperture created by the volumebetween the two tubes 255 and 256. Cooling liquid is circulated inside avolume 252 of inner tube 255, in order to enable stable light output andoperation of the light source. The small-diameter circular beam of lamp240 enables optimal collection of the generated light into light-guidesof various types, like light guide 15 shown in FIG. 1B and thelight-guide integrated to the treatment head shown below in FIG. 10.

FIG. 10 is a schematic side view of still another optical head 300 foruse in UVB or in dual-band phototherapy, in accordance with anotherembodiment of the present invention. The arrangement of head 300 issimilar to that of head 12, shown in FIG. 2, and only differences in thepresent embodiment are described here. Head 300 includes a UVB lightsource 310, based on the excimer lamp embodiment shown in FIG. 9B. Lightfrom source 310 is collimated by a lens module 314 and is furtherdirected in a small divergence angle into light guide 22. Cooling coils318 are used to cool the internal volume of the inner tube of lamp 310.Pump 320 circulates the cooling liquid in cooling coils 318. Coolingunit 318 and pump 320 are part of a dedicated liquid cooling module 315.

FIG. 11A is a schematic, pictorial illustration of a system 311 forphototherapeutic treatment of psoriasis and other skin disorders, inaccordance with another embodiment of the present invention. System 311comprises an optical head 313, which is used to collect and concentratethe light and irradiate the skin of a patient (not shown), who typicallylies on treatment table 14. Optical head 313 is coupled to and connectedthrough a flexible fiberoptic light guide 315 with a broad spectralpassband to a power supply and control console 317. Light guide 315 maycomprise a fiberoptic light-conducting bundle or a liquid-filledflexible light conductor, for example Lumatec Lightguide Series 250,produced by Lumatec (Munich, Germany).

Console 317 includes a light source (not shown in this figure) coupledto the light guide. The flexibility of the light guide allows anoperator 321 of system 311 to adjust the vertical, horizontal and radialplacement of optical head 313 relative to the patient's body. Amechanical or electromechanical elevation element 319 enables theadjustment of the fiber optic bundle output to the level required forthe specific treatment conditions. The light source is preferablycapable of providing radiation to light guide 315 in multiple differentwavelength bands, with automated selection of the desired bands, asdescribed hereinbelow.

Light guide 315 is preferably capable of conveying radiation with hightransmittance down to at least 290 nm. As noted above, a quartz fiberbundle may be used for this purpose. Alternatively, the light guide maycomprise a tube filled with UV-transmitting liquid. This latteralternative has the advantages of high transmittance (roughly 75% over atwo-meter length) and high numerical aperture (NA), typically about0.57. (By comparison the NA of quartz is about 0.24.) Suitable lightguides of this type are available from Lumatec and from Rofin (Perth,Australia), for example.

FIG. 11B is schematic, pictorial illustration of a system 330 forphototherapeutic treatment of psoriasis and other skin disorders, inaccordance with another embodiment of the present invention. In thisembodiment, optical head 12 is coupled to handheld treatment unit 313using light guide 315, which has a broad spectral band. Connectionbetween light guide 315 and optical head 12 is typically made through aquick-release, interchangeable mechanical interface. Optical head 12includes a light source and light collection optics (not shown in thisfigure) coupled to the fiber bundle. The flexibility of light guide 315provides ease in operational positioning and distancing of the lightexit aperture from the light source itself.

FIG. 12A is a schematic, sectional view of optics 350 for feedingradiation into light guide 315, in accordance with an embodiment of thepresent invention. Optics 350 may be used, for example, in console 317(FIG. 11A). A lamp 362 emitting UV radiation is positioned at the focusof an elliptical reflector 360, which concentrates the radiation fromthe lamp into light guide 315. A filter 352 selects the wavelength rangeor ranges to be admitted to the light guide. A hot mirror 354 isprovided to reflect long-wavelength radiation away from light guide 315,in order to avoid undue heating. A shutter 356 is controlled by a motor358 in order to block and open the light path to the light guide asdesired.

Preferably, lamp 362 comprises a gas discharge lamp, most preferably ahigh-pressure gas discharge lamp, such as a metal halide lamp. Theworking pressure inside such a lamp is typically in the range of 50-60atm. Examples of such lamps include the Osram (Munich, Germany) HBO 250lamp and the Perkin Elmer Optoelectronics (Wiesbaden, Germany) XHP200lamp. As noted above, certain additives may be used in the lamp toenhance emission in desired spectral bands, for example: bismuth for UVBemission; cesium or iron for UVA emission; and gallium for violet lightemission. A combination of such additives may be used to provide strongemission in multiple bands simultaneously. Because high-pressuredischarge lamps have a very small, intense arc (typically only 1-3 mmacross), the radiation from the lamp may be focused very efficientlyinto light guide 315. In fact, it may be desirable to place the lamp sothat the arc is slightly off the focus of reflector 360, in order toavoid creating a hot spot on the light guide. Alternatively, amedium-pressure lamp (working pressure of 1-3 atm) may be used.

Filter 352 may be one of a selection of filters provided in a filterwheel. Alternatively, other electrically or electromechanically tunableoptical filter types may be used, as are known in the art, such as PLZTor KDP crystals with appropriate polarizers. The choice of wavelengthrange or ranges may be controlled automatically by console 317,depending on the desired therapeutic modality, or manually by operator321. Preferably, the lamp and filters are chosen so as to allow multipledifferent therapeutic wavelength ranges to be used simultaneously,including not only UVB, but also UVA and visible (typically violet)light. Red and/or infrared radiation for specific desired treatmentrequirements may be selected and provided, too, as described above.Methods for selecting and controlling the wavelength and powercharacteristics of the radiation delivered through light guide 315 aredescribed in greater detail hereinbelow.

FIG. 12B is a schematic, pictorial illustration of one possibleembodiment of optics 350, showing further details of their mechanicalconstruction. The optics are mounted on a base 368. A mechanicalassembly 353 is used to select filter 352 by rotating the filter wheelin which the filter is held.

FIG. 12C is a schematic, sectional view of optics 400 for feedingradiation into light guide 315, in accordance with another embodiment ofthe present invention. In this case, the optical axis of reflector 360is turned 90° by a cold mirror 384, which reflects only short-wavelengthradiation. The wavelength band within which the cold mirror reflectsradiation may be chosen to give a sharp cut-on and cut-off, in order toselect the band of radiation to be conveyed by the light guide.Radiation outside this band passes through the cold mirror and isdiscarded.

Reflector 360 in this embodiment may be chosen to have a longer focallength than that in the embodiment of FIG. 12A. The longer focal lengthgives a longer focal path from lamp 362 to light guide 315, and thusallows a light guide with lower NA to be used without substantialradiation loss at the entrance to the light guide.

FIG. 12D is a schematic, sectional view of optics 450 for feedingradiation to light guide 315, in accordance with a further embodiment ofthe present invention. Optics 450 comprise three lamps 390, 392 and 394,which emit radiation in different, respective wavelength bands. Each ofthe lamps is provided with an elliptical reflector 380, 381 or 382, allof which are focused on the entrance to light guide 315. Typically, lamp390 operates in the shortest wavelength range, with lamps 392 and 394operating at successively longer wavelengths. Alternatively, larger orsmaller numbers of lamps may be used, with different wavelengtharrangements. Dichroic reflectors (beam-splitters) 384 and 385 are usedto combine the beams from the different lamps, substantially withoutloss. The undesired light bands that may be emitted by each lamp aretransferred through the dichroic reflectors, such as dichroic reflector385. This non-useful light energy is concentrated at a focal point 393,where a heat exchanger (not shown) may be placed in order to absorb andfurther discharge the heat generated by this ineffective energy. Lamps390, 392 and 394 are switched on and off in order to give the desiredwavelength band, or any combination of bands, in light guide 315.

FIG. 12E is a schematic, sectional view of optics 500 for feedingradiation to light guide 315, in accordance with an alternativeembodiment of the present invention. This embodiment is similar inprinciple to that of FIG. 12D, except that solid-state light sources458, 460 and 462 are used instead of arc lamps. The light sources maycomprise, for example, laser diodes or LEDs, operating in different,respective wavelength ranges. (Laser diodes and LEDs with wavelengthsdown to 290 nm and power levels in the tens of milliwatts are currentlyavailable from companies such as Nichia (Tokyo, Japan), and it isexpected that higher-power devices will be developed and becomecommercially available.) To provide sufficient optical power, thesolid-state light sources may be arranged in matrices on respectivesubstrates 452. The light sources may be fitted with lenses 454 orlenslet arrays in order to provide better collimation of their output.An objective 468 focuses the radiation into light guide 315. Thisarrangement is capable of providing several hundred milliwatts of UVBradiation at the input to the light guide and higher energy levels, inthe range of several watts, in the UVA and at selectable visiblespectral bands.

As in the preceding embodiment, dichroic mirrors or prisms are used tocombine the beams from the different light sources. The light sourcesare switched on and off in order to select the wavelength range orranges to be used in treating the patient.

Alternatively, solid-state light sources and one or more gas dischargelamps may be combined in a single system to provide multi-wavelengthinput to light guide 315. The radiation from the different types oflight sources may be combined by dichroic beamsplitters 384 and 385, ora hybrid optical arrangement of the type shown in FIG. 6B may be used.

FIG. 13 is a schematic, pictorial, partly cutaway view of a receptacle510 for receiving optical head 313, in accordance with an embodiment ofthe present invention. Receptacle 510 is typically integrated in console317, alongside a tray 323 used by operator 321 during treatment. Inbetween treatments, optical head 313 is inserted into receptacle 510.The optical head is constructed so that the end of light guide 315engages a solid lightguide quartz prism 429. (This is the end of thelight guide that is normally applied to the patient's skin.) The lightsource in console 317 is operated intermittently while the optical headis in the receptacle, in order to transmit radiation through light guide315. Radiation is thus emitted from the optical head, and is conveyed byprism 429 to a detector 425, typically a broadband thermal detector.

A controller 427 is coupled to measure the signal that is output bydetector 425, in order to determine the output level of the light guidein one or more of the wavelength bands provided by the system. Thecontroller is thus able to calibrate the power output of the system andverify that the power is within the expected range. This calibrationenergy output data may be used in subsequent treatments to increase ordecrease the power output of the radiation source in the console or,alternatively or additionally, to increase or decrease the duration oftreatment provided, so that the patient receives precisely the requiredradiation dosage. If the power measured by detector 425 is too faroutside the expected range, controller 427 may send an error signal tooperator 321, and may also block use of the system until the problem iscorrected.

FIGS. 14 and 15 are plots that schematically illustrate spectral bandsgenerated by system 311, for example, for use in phototherapy, inaccordance with embodiments of the present invention. These spectra wereobtained using a high-pressure metal halide arc lamp 362, withappropriate filters 352. In FIG. 14, a broad UVA spectral range isprovided, which may be used, for example, in treating atopic dermatitis.In FIG. 15, an interference filter with dual passbands is used to conveyboth UVB and violet radiation. This combination may be used, forexample, in simultaneously treating psoriasis (using UVB) and palliatinginflammation of the skin (using violet light).

Other wavelength combinations may also be provided by system 311, forexample:

-   -   UVA and violet radiation may be used together for treating        atopic dermatitis and inflammation.    -   Violet radiation may be used in conjunction with appropriate        chemical agents for photodynamic therapy (PDT).    -   UVA or violet radiation may be used for treatment of acne.    -   Red radiation, which penetrates deeper through the skin, may be        used for pain relief, as in treatment of erythritis, as well as        joint pain.        Therapeutic uses of violet light are described, for example, in        U.S. patent application Ser. No. 10/098,592, which is assigned        to the assignee of the present patent application, and whose        disclosure is incorporated herein by reference. Other        applications of the multi-wavelength capabilities of system 311        will be apparent to those skilled in the art.

FIGS. 16A-16E are schematic representations of computer screens used ina graphical user interface of system 311, in accordance with anembodiment of the present invention. System 311 preferably maintains adatabase of all patients who have been treated by the system. Thedatabase includes personal and health information regarding eachpatient, as well as records of treatment administered to date. Prior toinitiating treatment, operator 321 selects the current patient from thedatabase, or inputs patient information, if the current patient is beingtreated for the first time. Data entry screens (not shown) are providedfor this purpose.

As noted above, the appropriate dosage of UVB radiation to administer toa patient is typically determined based on the MED (Minimal ErythemaDose) for that patient. The MED is established by system 311 based on astandard test, which is controlled by operator 321 by means of a MEDtesting screen 500, shown in FIG. 16A. The operator determines theradiation dosage and exposure time to apply by selecting an on-screendosage button 502. The available dosages are suggested by system 311based on the patient's skin type, which is input by the operator andappears in a skin type window 504. By selecting different dosagebuttons, the operator can perform up to five different tests, atdifferent dosage levels, on different skin areas. Each test is initiatedby selecting a start button 506, and the procedure may be terminated byselecting a stop button 508.

The operator then observes, after 24-48 hours, the erythema that appearson the patient's skin as a result of each test, and based on thisobservation, records the MED for the patient in the database of system311. This MED level is used in determining subsequent dosage. A similarprocedure may be used to determine the patient's MPD (Minimum PhototoxicDose) for UVA treatment In order to select the type of treatment toadminister the patient, operator 321 next selects a diagnosis, in anindications screen 520, shown in FIG. 16B. Screen 520 offers threetreatment windows: a UVB window 522, a UVA window 524 and a UV/visiblewindow 526. Each window contains buttons 530 and 532 providing differentindications. A first button type 530 refers to indications for whichthis patient has already been treated (psoriasis, in the presentexample), as recorded in the database of system 311. A second buttontype 532 refers to all other indications. As shown in the figure, system311 offers the following treatment options:

-   -   UVB treatment for psoriasis, vitiligo and certain scar types.    -   UVA treatment for kelloids, atopic dermatitis and morphea, as        well as phototesting.    -   Combined UVA/violet light treatment for atopic dermatitis.    -   Visible light application for PDT.        Other indications may also be added, of course, either as an        extension of the software options offered by system 311, or by        the operator.

Based on the diagnosis, together with the patient records and treatmenthistory stored in the database, system 311 allows operator 321 to selectthe dosage to be applied in this treatment, using a treatment screen540, as shown in FIG. 16C. In the present example, in which the patientis diagnosed with psoriasis, a UVB dosage is recommended, and appears ina UVB window 542. Additional windows 544 and 546 are available forcontrolling UVA and visible radiation dosages. Typically, the operatorselects the UVB dosage in units of MEDs, based on the MED determined forthis patient, as described above. The operator may increase or decreasethe number of MEDs to apply using a MED control 548. System 311 thendetermines automatically the intensity and duration of radiation toapply.

Alternatively, the operator may use a dose control 550 and a durationcontrol 552 to manually increase or decrease the intensity and/orduration of the radiation dose. If a MED level is set, and the operatorchanges the intensity, for example, system 311 will automaticallydecrease the duration of exposure, and vice versa. For safety reasons,the system preferably limits the dosage to a predetermined maximum,typically 8 MEDs. The operator may also choose to apply either pulsed orcontinuous radiation, using mode control buttons 554.

To begin treatment, the operator presses a start button 556, or a footpedal (not shown) attached by a cable to the system. Treatment may beterminated by pressing a stop button 558, when operating in a continuousmode. Otherwise, treatment automatically stops when the selected MED ordose has been given in pulsed mode. A bar graph 560 shows the progressof the treatment exposure duration.

As noted above, system 311 maintains a database “file” for each patient,which includes the history of treatments the patient has undergone,including digital images of the treated skin areas. The database recordsare updated after each treatment, or when operator 321 inputs new data.The data in the files can be read by the operator in alphanumeric,graphic and tabular forms.

FIG. 16D shows a graphic screen 570, giving the treatment history of asample patient. The progress of the patient's condition over time isshown in a graph 572. The graph may be marked to show dates of treatmentand assessment. A numerical window 574 shows numerical values ofcomputed diagnostic data, as well. The operator may also input and storepictorial records, to track the patient's progress. In the presentexample, successive images 578 and 580 of this sort are displayed in apicture window 576.

FIG. 16E shows an assessment screen 590, which is used by operator 321to record the patient's condition periodically. Various diagnosticparameters can be input and/or calculated using this screen. Forexample, the operator may delineate the area of a lesion on an image599, and may calculate the area of the lesion, using an area calculationwindow 592. The area is typically displayed as a percentage of theoriginal area of the given lesion, before the course of treatment began.The operator may also input scores corresponding to the redness, scalinglevel and elevation of the lesion, as shown in scaling and elevationwindows 594 and 596. The level of erythema may be recorded in anerythema window 598. These visual inspection parameters, rated on ascale of 1 to 4, are used to calculate a Psoriasis Score Indicator(PSI), which is the sum of the three inspection parameters. Theseparameters allow the operator to track the patient's status over time,using screen 570, for example, and to modify treatment parameters asrequired.

Although the embodiments described above make reference to particularindications for phototherapy, and make use of certain types ofequipment, the principles of the present invention may similarly beapplied to treat other skin conditions, in other equipmentconfigurations. It will thus be appreciated that the embodimentsdescribed above are cited by way of example, and that the presentinvention is not limited to what has been particularly shown anddescribed hereinabove. Rather, the scope of the present inventionincludes both combinations and subcombinations of the various featuresdescribed hereinabove, as well as variations and modifications thereofwhich would occur to persons skilled in the art upon reading theforegoing description and which are not disclosed in the prior art.

1-7. (canceled)
 8. Apparatus for treatment of a skin condition,comprising: a radiation source, adapted to irradiate an area of the skinwith radiation in at least one of an ultraviolet, visible and infraredspectral range; and marking means, adapted to delineate the area on theskin responsive to irradiation of the area by the radiation source,wherein the marking means comprises one or more markers, adapted toprint a plurality of marks on the skin delineating the irradiated area,and comprising an arm supporting the radiation source, and an imagingdevice coupled to capture an image of the skin, and a processor adaptedto analyze the marks on the skin appearing in the image so as to guidethe radiation source by controlling movement of the arm, responsive tothe marks in the image.
 9. Apparatus for treatment of a skin condition,comprising: a radiation source, adapted to irradiate an area of the skinwith radiation in at least one of an ultraviolet, visible and infraredspectral range; and marking means, adapted to delineate the area on theskin responsive to irradiation of the area by the radiation source,wherein the radiation source comprises a radiation guide, which isbrought into proximity with the area of the skin so as to deliver theradiation thereto, and wherein the marking means is adapted to mark aperiphery of the radiation guide.
 10. Apparatus for treatment of a skincondition, comprising: a radiation source, adapted to irradiate an areaof the skin with radiation in at least one of an ultraviolet, visibleand infrared spectral range; and marking means, adapted to delineate thearea on the skin responsive to irradiation of the area by the radiationsource, wherein the marking means comprises a photosensitive substance,which is applied to the skin prior to irradiating the area of the skin,and wherein the radiation causes a visible change in the photosensitivesubstance, thereby delineating the area. 11-15. (canceled)
 16. A methodfor treatment of psoriasis, comprising: irradiating a psoriatic area ofskin with ultraviolet (UV) radiation, so as to treat the psoriasis;detecting an optical quality of the irradiated area; and controlling alevel of the radiation responsive to the indication.
 17. A methodaccording to claim 16, and comprising, prior to irradiating thepsoriatic area of the skin, applying a quickly-solidifying, self-peelingcream or gel material, having UV energy protection capability includingat least one of absorption and reflection properties, to a healthy skinarea on a periphery of the psoriatic area. 18-23. (canceled) 24.Apparatus for treatment of skin disorders, comprising: a radiationsource, adapted to generate ultraviolet (UV) radiation suitable fortreatment of skin affected by one or more of the skin disorders; andradiation delivery optics, coupled to the radiation source so as toconcentrate and deliver the generated UV radiation directly to theaffected skin with an energy flux level per single treatment andspecific affected skin area selected from an energy radiation flux groupconsisting of at least a radiation flux equal or higher than 50 mJ/cm²in less than 30 sec per treatment and a radiation flux higher than 1.5MED (Minimum Erythema Dose), wherein the UV radiation is in a spectralrange of 296-390 nm and comprises at least one spectral line ofsubstantial intensity having a bandwidth of at least 1 nm, wherein thespectral line is selected so as to engender clearing of the affectedskin, and wherein the radiation delivery optics are adapted to limit anexposure area of the radiation to the affected skin.
 25. Apparatusaccording to claim 24, wherein the radiation delivery optics compriseone of a selection of interchangeable light guides, which are adapted todirect the radiation toward the affected skin during the treatment, andwherein the light guides are selectable so as to match an outputaperture of the selected light guide to a size and shape of the affectedskin.
 26. Apparatus according to claim 25, wherein the output aperturesof the interchangeable light guides are selected from a group includingaperture areas of at least 200 mm², 400 mm² and 2500 mm².
 27. Apparatusaccording to claim 25, wherein the radiation delivery optics furthercomprise aperture shaping optics at the output aperture so as to providean aperture shape that is adapted for optimal plaque area energycoverage.
 28. Apparatus according to claim 24, and comprising a modulecontaining the radiation source and the radiation delivery optics, andan articulated arm, which is coupled to suspend and position the modulerelative to the affected skin. 29-30. (canceled)
 31. Apparatus fortreatment of skin disorders, comprising: a radiation source, adapted togenerate ultraviolet (UV) radiation suitable for treatment of skinaffected by one or more of the skin disorders; and radiation deliveryoptics, coupled to the radiation source so as to concentrate and deliverthe generated UV radiation directly to the affected skin with an energyflux level per single treatment and specific affected skin area selectedfrom an energy radiation flux group consisting of at least a radiationflux equal or higher than 50 mJ/cm² in less than 30 sec per treatmentand a radiation flux higher than 1.5 MED (Minimum Erythema Dose),wherein the UV radiation is in a spectral range of 296-390 nm andcomprises at least one spectral line of substantial intensity having abandwidth of at least 1 nm, wherein the spectral line is selected so asto engender clearing of the affected skin, and wherein the radiationsource is adapted to provide a continuous energy output during treatmentof the affected skin, with a momentary output peak power smaller than 10kW/cm².
 32. Apparatus for treatment of skin disorders, comprising: aradiation source, adapted to generate ultraviolet (UV) radiationsuitable for treatment of skin affected by one or more of the skindisorders; and radiation delivery optics, coupled to the radiationsource so as to concentrate and deliver the generated UV radiationdirectly to the affected skin with an energy flux level per singletreatment and specific affected skin area selected from an energyradiation flux group consisting of at least a radiation flux equal orhigher than 50 mJ/cm² in less than 30 sec per treatment and a radiationflux higher than 1.5 MED (Minimum Erythema Dose), wherein the UVradiation is in a spectral range of 296-390 nm and comprises at leastone spectral line of substantial intensity having a bandwidth of atleast 1 nm, wherein the spectral line is selected so as to engenderclearing of the affected skin, and wherein the apparatus is adapted todetermine the radiation flux corresponding to the MED by determining aminimum energy dosage creating erythema on normal skin in a vicinity ofthe affected skin area, whereby operating parameters of the apparatusare set to the radiation flux thus determined.
 33. Apparatus fortreatment of skin disorders, comprising: a radiation source, adapted togenerate ultraviolet (UV) radiation suitable for treatment of skinaffected by one or more of the skin disorders; and radiation deliveryoptics, coupled to the radiation source so as to concentrate and deliverthe generated UV radiation directly to the affected skin with an energyflux level per single treatment and specific affected skin area selectedfrom an energy radiation flux group consisting of at least a radiationflux equal or higher than 50 mJ/cm² in less than 30 sec per treatmentand a radiation flux higher than 1.5 MED (Minimum Erythema Dose),wherein the UV radiation is in a spectral range of 296-390 nm andcomprises at least one spectral line of substantial intensity having abandwidth of at least 1 nm, wherein the spectral line is selected so asto engender clearing of the affected skin, and wherein the radiationsource further comprises at least a second source of radiation suitableto photothermolyze blood vessels in a vicinity of the affected skin. 34.Apparatus according to claim 33, wherein the second radiation sourcecomprises a pulsed source emitting at least one of visible radiation andnear infrared (NIR) radiation.
 35. Apparatus for treatment of skindisorders, comprising: a radiation source, adapted to generateultraviolet (UV) radiation suitable for treatment of skin affected byone or more of the skin disorders; and radiation delivery optics,coupled to the radiation source so as to concentrate and deliver thegenerated UV radiation directly to the affected skin with an energy fluxlevel per single treatment and specific affected skin area selected froman energy radiation flux group consisting of at least a radiation fluxequal or higher than 50 mJ/cm² in less than 30 sec per treatment and aradiation flux higher than 1.5 MED (Minimum Erythema Dose), wherein theUV radiation is in a spectral range of 296-390 nm and comprises at leastone spectral line of substantial intensity having a bandwidth of atleast 1 nm, wherein the spectral line is selected so as to engenderclearing of the affected skin, and wherein the radiation sourcecomprises a metal halide lamp, whose output spectrum comprises spectrallines at 303, 306, 308, 309, and 312 nm. 36-42. (canceled)
 43. Apparatusfor treatment of skin disorders, comprising: a radiation source, whichis adapted to generate radiation in multiple spectral bands; a radiationguide, which is optically coupled to receive the radiation in all of themultiple spectral bands, and to convey the received radiation to an areaof skin affected by one of the disorders, so as to treat the affectedarea; and a band selector, which is adapted to select one or more of themultiple spectral bands to be conveyed by the radiation guide, inresponse to a therapeutic indication, wherein the multiple spectralbands comprise at least one band in each of an ultraviolet A (UVA)range, an ultraviolet B (UVB) range, and a visible range.
 44. Apparatusaccording to claim 43, wherein the visible range comprises a violetlight range.
 45. Apparatus according to claim 43, wherein the visiblerange comprises a red light range.
 46. Apparatus according to claim 43,wherein the band selector is adapted to select at least two of thespectral bands to be conveyed by the radiation guide simultaneously. 47.Apparatus according to claim 46, wherein the at least two of the bandscomprise the at least one band in one of the UVA and UVB ranges and theat least one band in the visible range.
 48. Apparatus according to claim47, wherein the at least one band in the one of the UVA and UVB rangescomprises one or more wavelengths in the UVB range that provideeffective treatment of a psoriatic plaque, while the at least one bandin the visible range comprises violet light suitable for treatinginflammation associated with the plaque.
 49. Apparatus for treatment ofskin disorders, comprising: a radiation source, which is adapted togenerate radiation in multiple spectral bands; a radiation guide, whichis optically coupled to receive the radiation in all of the multiplespectral bands, and to convey the received radiation to an area of skinaffected by one of the disorders, so as to treat the affected area; anda band selector, which is adapted to select one or more of the multiplespectral bands to be conveyed by the radiation guide, in response to atherapeutic indication, wherein the radiation source comprises aplurality of lamps, each operating in one or more of the spectral bands,and a beam combiner for combining the radiation from the plurality ofthe lamps to be received by the radiation guide.
 50. Apparatus accordingto claim 49, wherein the plurality of lamps comprise electricaldischarge lamps.
 51. Apparatus according to claim 49, wherein theplurality of lamps comprise solid-state light sources.
 52. Apparatusaccording to claim 49, wherein the plurality of lamps comprise at leastone electrical discharge lamp and at least one solid-state light source.53. Apparatus according to claim 49, wherein the beam combiner comprisesone or more dichroic mirrors, which are adapted to selectively reflectthe radiation emitted by the lamps.
 54. Apparatus according to claim 49,wherein the band selector is arranged to actuate one or more of thelamps to operate so as to provide the selected one or more of thespectral bands.
 55. Apparatus for treatment of skin disorders,comprising: a radiation source, which is adapted to generate radiationin multiple spectral bands; a radiation guide, which is opticallycoupled to receive the radiation in all of the multiple spectral bands,and to convey the received radiation to an area of skin affected by oneof the disorders, so as to treat the affected area; and a band selector,which is adapted to select one or more of the multiple spectral bands tobe conveyed by the radiation guide, in response to a therapeuticindication, wherein the band selector comprises one or more opticalfilters, having a selectable spectral passband.
 56. Apparatus fortreatment of skin disorders, comprising: a radiation source, which isadapted to generate radiation in multiple spectral bands; a radiationguide, which is optically coupled to receive the radiation in all of themultiple spectral bands, and to convey the received radiation to an areaof skin affected by one of the disorders, so as to treat the affectedarea; and a band selector, which is adapted to select one or more of themultiple spectral bands to be conveyed by the radiation guide, inresponse to a therapeutic indication, wherein the radiation guidecomprises at least one of a fiberoptic light guide and a liquid-filledlight guide.
 57. Apparatus for treatment of skin disorders, comprising:a radiation source, which is adapted to generate radiation in multiplespectral bands; a radiation guide, which is optically coupled to receivethe radiation in all of the multiple spectral bands, and to convey thereceived radiation to an area of skin affected by one of the disorders,so as to treat the affected area; and a band selector, which is adaptedto select one or more of the multiple spectral bands to be conveyed bythe radiation guide, in response to a therapeutic indication, whereinthe radiation guide comprises a proximal end, which is coupled toreceive the radiation, and a distal end, which is adapted to deliver theradiation to the area of the skin, and further comprising: a receptacle,for receiving the distal end of the radiation guide; a detector, whichis coupled to receive the radiation emitted from the distal end of theradiation guide when the radiation guide is inserted in the receptacle,and to generate a signal in response to an intensity of the radiation;and a controller, which is coupled to receive the signal from thedetector and to determine, based on the signal, an output level of theapparatus.
 58. Apparatus according to claim 57, wherein the controlleris adapted to adjust an operating level of the radiation source inresponse to the signal, so as to adjust the output level to apredetermined value.
 59. Apparatus for treatment of skin disorders,comprising: a radiation source, which is adapted to generate radiationin multiple spectral bands; a radiation guide, which is opticallycoupled to receive the radiation in all of the multiple spectral bands,and to convey the received radiation to an area of skin affected by oneof the disorders, so as to treat the affected area; and a band selector,which is adapted to select one or more of the multiple spectral bands tobe conveyed by the radiation guide, in response to a therapeuticindication, and comprising a controller having a user interface, whichis operable by an operator of the apparatus to input the therapeuticindication to the band selector.
 60. Apparatus according to claim 59,wherein the user interface is further operable by the operator toinitiate a procedure, using the apparatus, for determining a MinimalErythema Dose (MED) of a patient in treatment, and wherein thecontroller is adapted to set a level of the radiation to be applied tothe affected area of the skin of the patient based on the determinedMED.
 61. Apparatus according to claim 59, wherein the controllercomprises a memory, and wherein the user interface is further operableby the operator to record and recall a treatment history of a patient intreatment using the apparatus. 62-67. (canceled)
 68. A method fortreatment of skin disorders, comprising: directing radiation in multiplespectral bands toward an input end of a radiation guide; selecting oneor more of the multiple spectral bands to be input to the radiationguide through the input end, in response to a therapeutic indicationwith respect to an area of skin affected by one of the disorders; andapplying an output end of the radiation guide to the affected area ofthe skin as to treat the affected area, wherein the multiple spectralbands comprise at least one band in at least two spectral rangesselected from the group consisting of ultraviolet A (UVA) range, anultraviolet B (UVB) range, and a visible range, and wherein selectingthe one or more of the multiple spectral bands comprises selecting atleast two of the spectral bands to be conveyed by the radiation guidesimultaneously, and wherein the at least two of the bands comprise theat least one band in one of the UVA and UVB ranges and the at least oneband in the visible range, and wherein the at least one band in one ofthe UVA and UVB ranges comprises one or more wavelengths in the UVBrange that provide effective treatment of a psoriatic plaque, while theat least one band in the visible range comprises violet light suitablefor treating inflammation associated with the plaque.
 69. A method fortreatment of skin disorders, comprising: directing radiation in multiplespectral bands toward an input end of a radiation guide; selecting oneor more of the multiple spectral bands to be input to the radiationguide through the input end, in response to a therapeutic indicationwith respect to an area of skin affected by one of the disorders; andapplying an output end of the radiation guide to the affected area ofthe skin as to treat the affected area, wherein selecting the one ormore of the multiple spectral bands comprises receiving an input of thetherapeutic indication from an operator, and selecting the one or moreof the spectral bands automatically in response to the input.
 70. Amethod for treatment of skin disorders, comprising: directing radiationin multiple spectral bands toward an input end of a radiation guide;selecting one or more of the multiple spectral bands to be input to theradiation guide through the input end, in response to a therapeuticindication with respect to an area of skin affected by one of thedisorders; and applying an output end of the radiation guide to theaffected area of the skin as to treat the affected area, whereindirecting the radiation comprises determining a Minimal Erythema Dose(MED) of a patient in treatment, and setting a level of the radiation tobe applied to the affected area of the skin of the patient based on thedetermined MED.